Lymphoma (other than lymphoma of the brain): Patients with a history of successfully treated lymphoma are eligible, provided full remission was obtained at least 5 years prior to randomization. Full remission (or complete response) is defined as the absence of clinically detectable disease with normalization of any previously abnormal radiographic studies, and bone marrow examination. Patients with bone marrow positive lymphoma prior to chemotherapy must have had two repeat bone marrow examinations negative for lymphoma after chemotherapy at least 12 months prior to randomization.